Unauthorized debits and suspension of Internet

I took out a wifi contract fromTelkom. It was capped at R298 a month. After 4 months of taking the contract, more money was being deducted from my account. I went to the store to inquire, I was told it's a mistake. I never received my refund. Instead head office told me that they can debit any amount they way. This continued to such an extent where I had to reverse other unauthorized debits from Telkom. Soon afterward I was sent an SMS that informed about suspending my internet due to non payment. However, I don't owe them a penny.